Bistable operating reed relay



Jan. 9, 1968 SCHADEWQALD 3,363,203

BISTABLE OPERATING REED RELAY Filed May 12, 1966 Fig.2

United States Patent BISTABLE OPERATING REED RELAY Dieter Schadewald, Merklingen, Germany, assignor to International Standard Electric Corporation Filed May 12, 1966, Ser. No. 549,519 Claims priority, application Germany, May 20, 1965, St 23,854 4 Claims. (Cl. 33579) ABSTRACT OF THE DISCLOSURE A bistable reed relay is operated from one stable condition to another when a permanent magnet that controls the contacts is moved from one position to another responsive to the operation of an electromagnet.

The invention relates to reed relays and more particularly to bistable operating reed relays. Two magnetic elements are used to switch the relays from first stable operating positions to second stable operating positions and vice versa.

Electromagnetic relays with reed contacts are known.

It is also known to actuate reed contacts with permanent magnets. The relative position of the permanent magnet in relation to the reed contacts being changed to actuate the contacts.

It is also known to use electromagnets for moving the permanent magnets and thus through the changing of the magnets position, reed contacts are actuated. In such devices, the permanent magnets are firmly connected with the armature of a cam-type electric magnet, for example through a rod. After the excitation voltage of the electromagnet has been switched off, the permanent magnet returns to its normal position with a spring. The above described device is a mono-stable electric switching device using two magnetic elements.

Moreover, bistable magnetic arrangements with two magnet elements have been proposed to actuate reed contacts. In the proposed arrangements two axially magnetized permanent magnets move along parallel paths whereby one permanent magnet slides on the reed tube as an annular ring-shaped magnet. Both permanent magnets can move to posterior or anterior limit positions where they are kept by their repellent magnetic effect.

Each limit position of the permanent magnet sliding on the.

It is the object of the invention to provide a bistable operating reed relay, which is brought from one stable operative condition into the other stable operative condition by a current surge and remains in that second operative condition even after the excitation current has been switched off. Reversing the current direction, however, returns the relay into the original stable condition.

This object is achieved, according to a preferred embodiment of the invention, by using one magnetic element that comprises an electromagnet and a second mag netic element of a permanent magnet. The ferromagnetic circuit of the electromagnet is such that, when the electromagnet is excited with a current surge, the second magnetic element which is magnetized in its longitudinal direction and movably mounted within the magnetic held of the electromagnet, always changes its stable position, thereby actuating the reed contact. When the electromagnet is excited both poles of the permanent magnet face poles of the electromagnet that are the same, either both north poles or both south poles. The permanent 3,363,203 Patented Jan. 9, 1968 magnet is moved in the direction of its opposite pole, compared with the poles of the electromagnet.

According to an embodiment of the invention, the poles of the elemtromagnet, facing the poles of the permanent magnet, simultaneously serve as limits for the permanent magnets and the permanent magnets adheres to either one of said limits, until it is moved to the opposite limit, by changing the polarity of the electromagnetic field.

According to a further embodiment of the invention, the force of the permanent magnet at the limits can be modified through separating metal sheets.

According to a further embodiment of the invention, suitably shaped flux guiding metal sheets are provided to improve the magnetic field intensity of the electromagnet, carrying back the second magnetic pole of the electromagnet into the vicinity of the permanent magnet.

According to a further embodiment of the invention, the permanent magnetic element is a ring-shaped magnet which slides on the reed tube.

According to a further embodiment of the invention, several permanent magnets are associated with one correspondingly dimensioned electromagnet for actuating reed contacts.

The bistable operating relay, according to the invention, has many advantages. As the relay is equipped with reed contacts, for example, all advantages known for using reed contacts also apply for therelay according to the invention. Its simple construction guarantees a cheap production. Moreover, the relay may 'be equipped with different types of reed contacts, known per se, e.g. blade armature contacts, twin contacts, ball-type armature contacts.

The above mentioned and other features of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows the construction of an embodiment of the bistable operating relay according to the application in principle, seen from the side and partly in section; and

FIG. 2 shows the arrangement of the electromagnet,

forming the poles, towards the permanent magnet, in a g three-dimensional representation.

FIG. 1 shows the coil of the electromagnet l. The coil body 2 surround the iron core 3, which extends to form the poles. This core is divided on the pole ends into the two stops or limits 4 and 5 through which the magnetic flux passes. The opposite end of the core 3 is connected by the iron hull 6. The iron hull 6 terminatesin flux guiding metal sheets 7, which serve to improve the magnetic field intensity. The ring-shaped permanent magnet 8 is arranged on the reed tube 9, and slides between the stops 4 and 5. The disconnecting metal sheets 10 and 11 form a magnetic airgap between the stops 4 and 5 and the ring-shaped magnet 8. FIG. 1 shows, as an example, a ball-type reed contact.

FIG. 2 shows the arrangement of the stops 4 and 5, forming the poles, and the flux guiding metal sheets 7 which direct the electromotive generated flux towards the ring-shaped magnet 8. At the magnetic flux conditions shown on the drawings, the ring-shaped magnet moves in the direction of the bottom stop 5.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

I claim:

1. A bistable reed relay comprising reed switch means operated with the aid of a first and a second magnetic element from one stable condition to a second stable condition, said first magnetic element comprising an electromagnet, said electromagnet consisting of a single coil, said electromagnet further comprising core means surrounded by said single coil, said core means terminating in a pair of pole pieces of similar polarity, said pole pieces lying in planes parallel to the plane of said core means for supporting said reed relay between only normal to said pole pieces, said second magnetic element comprising a permanent magnet magnetized in the longitudinal direction positioned between said pole pieces and arranged to slide with the field of said first magnetic element between a first and a second stable position along said reed relay, said first magnetic element further comprising a ferromagnetic circuit which is formed so that when the electromagnet is excited by a surge of current the second magnetic element changes its respective stable position and magnetically actuates the reed contacts.

2. A bistable relay according to claim 1, wherein both pole pieces of ahe said permanent magnet face the homologous poles of the electromagnet when said electromagnet is excited, whereby the permanent magnet is moved in the direction of its pole that is of a polarity opposite to. the polarity of said homologous pole pieces of electromagnet.

3. A bistable relay according to claim 2 wherein disconnectable metal sheet means are provided for modifying the attractive force between the permanent magnet and the stops.

4. A bistable relay according to claim 2 wherein the flux guiding metal sheets are provided for improving the magnetic field intensity of the electromagnet, the said metal sheets act as the second poles for the electromagnet and terminate in the vicinity of the permanent magnet.

References Cited UNITED STATES PATENTS 3,284,74l 11/1966 Conklin 335-154 BERNARD A. GILHEANY, Primaly Examiner.

20 H. BROOME, Assistant Examiner. 

